Karl Guthe Jansky

Physicist and radio engineer

• Born: October 22, 1905
• Birthplace: Territory of Oklahoma
• Died: February 14, 1950
• Place of death: Red Bank, New Jersey

American physicist

Twentieth-century American physicist and engineer Karl Guthe Jansky spent his career at Bell Telephone Laboratories. In the course of completing an assignment for the company, he detected radio signals emanating from the center of the Milky Way Galaxy, laying the foundation for a new branch of astronomy.

Born: October 22, 1905; Norman, Oklahoma Territory (now Oklahoma)

Died: February 14, 1950; Red Bank, New Jersey

Primary field: Physics

Specialties: Electromagnetism; astrophysics; theoretical astronomy

Early Life

Karl Guthe Jansky (kahrl gewth JAN-skee) was born in Oklahoma Territory just two years before it became a state. He was the third of six children of Cyril M. Jansky and Nellie Moreau Jansky. His father, a physicist and electrical engineer, was head of the engineering department at the University of Oklahoma. Jansky, his elder brother Cyril Jr., and his younger brother Maurice all followed their father into engineering. It was perhaps inevitable that Jansky became a scientist: He was named after physicist Karl Guthe, who had taught and mentored his father at the University of Michigan.

When Jansky was three years old, he moved with his family to Wisconsin, where his father became a professor of electrical engineering. Jansky attended Central High School in Madison, where, despite chronic kidney problems, he became an excellent athlete and an outstanding student. After graduation, he attended the University of Wisconsin–Madison, where he played tennis and starred on the university’s ice-hockey team. A member of the Phi Beta Kappa honor society, Jansky graduated cum laude, earning a bachelor of science degree in physics in 1927. Afterward, he spent a year teaching part time at the university and took several graduate-level courses in his specialty.

In 1928, Jansky applied for a job at Bell Telephone Laboratories (Bell Labs), but he was initially refused a position because of his uncertain health. His brother Cyril, a teacher at the University of Minnesota who had formerly worked at the Bell Labs, put in a good word for him, and he was subsequently hired. He spent the rest of his adult life working for Bell Labs.

Life’s Work

Originally part of the American Telephone and Telegraph Company (AT&T) and later a subsidiary of Alcatel-Lucent, Bell Labs was created as a research and development entity in New Jersey in 1925. During most of its existence, Bell Labs was a breeding ground for advanced technology. In its heyday, between the 1920s and 1980s, the company had almost fifteen thousand employees and churned out scores of patented inventions that continue to affect lives worldwide. Between 1937 and 2009, Bell scientists garnered seven Nobel Prizes for such accomplishments as the invention of the transistor and the revelation of cosmic microwave background radiation. When Jansky joined the Bell team in 1928, he had little idea that his work would also lead to a Nobel Prize–caliber discovery.

In 1929, Jansky married Alice Knapp, who would become mother to their two children. That same year, he was assigned to Bell Labs’ facility at Cliffwood (later moved to Holmdel) in New Jersey. He was given the task of investigating and attempting to solve the problem of static, which interfered with shortwave radio transmissions and disrupted the company’s lucrative overseas radiotelephone service.

To analyze the cause of the static, Jansky designed and built a thirty-meter-wide antenna that was then mounted on a motor-driven turntable supported by automobile tires so it could rotate 360 degrees to locate and focus on the origin of the static. He also designed a receiver to amplify static-laden signals and connected a recorder to document the sounds of the static.

For many months, Jansky recorded static outbursts received at the wavelength for which his equipment was set (usually 14.6 meters). By 1932, he had divided the bursts of static into three types. Two types, which comprised the majority of the recorded signals, were crackling discharges caused by near or distant thunderstorms, as became obvious from comparisons with reports of lightning. The third type of static, however, was different—a steady hiss.

At first, Jansky supposed the hiss was the result of radiation from the sun. Further studies, however, revealed that the interference came from deep space. Jansky pinpointed the source of the signal as the dense center of the Milky Way Galaxy, in the vicinity of the constellation Sagittarius.

Jansky revealed his findings in a 1932 presentation to the International Union of Radio Science in Washington, DC. The following year, he published “Electric Disturbances Apparently of Extraterrestrial Origin,” the first of three papers he wrote regarding the phenomenon of interstellar noise. Jansky’s observations were also described in a front-page article in the New York Times on May 5, 1933, and a national radio program even broadcast a few seconds of cosmic radio noise. Coming as they did in the depths of the Great Depression, the announcements aroused scant interest. Jansky hoped to pursue his discovery further and petitioned his employer to build a larger antenna. However, since there was no way the outer-space hiss—which caused only slight, occasional interference to shortwave transmission—could be eliminated, Bell Labs ended the project and reassigned the young physicist.

Jansky spent the remaining seventeen years of his career with the company in other work of relatively minor importance in the general area of radio communications. However, he was able to use his research as the basis for his thesis, which completed the requirements for his master of science degree, earned at the University of Wisconsin in 1936. Plagued with recurring physical problems, he succumbed to kidney failure in 1950 at the age of forty-four.

Impact

Jansky’s discovery of radio waves from space had little initial effect on the scientific community. In 1937, engineer and amateur astronomer Grote Reber constructed his own improved antenna to duplicate Jansky’s experiments, in effect building what would be known as the first radio telescope. Reber expanded on Jansky’s work, conducting a survey of radio frequencies from space.

Radio astronomy remained dormant until the late 1940s. Given impetus through the development of radar for World War II, the new science began blossoming during the 1950s and grew rapidly from the 1960s, thanks to the efforts of such microwave researchers as Robert Wilson, Robert H. Dicke, Ralph Alpher, James Peebles, and Nobel Prize-winner Arno Allan Penzias.

In the twenty-first century, radio astronomy, which gathers information not obtainable by traditional visual methods of observation, is well established as a discipline, thanks in part to the founding of the National Radio Astronomy Observatory (NRAO) in 1956. Research conducted from NRAO facilities in Charlottesville, Virginia; Green Bank, West Virginia; Socorro, New Mexico; Tucson, Arizona; and Santiago, Chile (and from large arrays in Europe, China, South Africa, Australia, and Puerto Rico) have identified numerous extraterrestrial sources of radio emission—stars, galaxies, quasars, and pulsars—and have reinforced the big bang theory of the universe’s creation. An offshoot of radio astronomy, the search for extraterrestrial intelligence (SETI) uses sophisticated equipment descended from the instruments Jansky pioneered to monitor electromagnetic radiation for indications of purposeful transmissions from alien worlds that would prove humans are not alone in the universe.

Though his work was largely ignored during his lifetime, Jansky has received considerable posthumous recognition. In the 1970s, the System International (SI) introduced the jansky (Jy) as a measurement (10^-26 watts per square meter per hertz) of flux density or radio-wave strength. In 1998, Bell Labs erected a monument to Jansky on the site of his original antenna. A crater on the moon is named after Jansky. The NRAO named a lab, a lectureship, and a fellowship in his honor and, in 2012, renamed their New Mexico facility (prominently featured in Armageddon (1998), Independence Day (1996), and other films) the Karl G. Jansky Very Large Array.

Bibliography

Gray, Robert H. The Elusive Wow: Searching for Extraterrestrial Intelligence. Chicago: Palmer Square, 2011. Print. Discusses the development of interstellar radio detection, which, after initiation by Jansky, led to the science of radio astronomy and ultimately to the search for advanced life on other worlds.

Schilling, Govert. Atlas of Astronomical Discoveries. New York: Springer, 2011. Print. An illustrated overview of the most important advancements in the field of astronomy since the 1600s, beginning with the invention of the telescope and including Jansky’s discovery of radio emission from space.

Verschuur, Gerrit. The Invisible Universe: The Story of Radio Astronomy. 1974. New York: Springer, 2010. Print. Details the history of the subspecialty of radio astronomy, from Jansky’s experiments to the present. Contains many photographs, illustrations, glossaries, and appendixes.